Carotenoids are widely used across the pharmaceutical, neutraceutical, cosmetic, food and feed industries. The compositions are collectively referred to as nutritional compositions in this specification. In the feed industry, carotenoids have utility as colourant additive and essential nutrients. Delivering carotenoids that have good absorption and bioavailability is a major problem because the compounds are practically insoluble in water at ambient temperatures. Specific examples are astaxanthin and canthaxanthin for aquaculture and beta carotene and zeaxanthin for the poultry industry. Poor solubility is a major hurdle to good bioavailability. The crystalline forms of these carotenoids are not used as such because of poor dissolution characteristics and have therefore to be formulated first to become useful feed and nutrient additives. Particulate compositions prepared by spray drying or catch beadlet technology described in U.S. Pat. No. 2,756,177 containing astaxanthin or canthaxanthin in a polymer matrix are extensively used in feed production. The dispersible beadlets or granules are added as dry powders or they may be dissolved/dispersed in water before or after processing into feed compositions.
The present disclosure is for preparing oily carotenoid solutions by dispersing carotenoids which may be crystals, amorphous particles or aggregates and combinations thereof in oil and dissolving the carotenoid in heated oil phase followed by cooling preferably with an oil phase using a continuous in-line method. The resulting oily carotenoid composition may be used as such directly for preparing feed and other compositions. The method does not require the carotenoid to be formulated as colloid-dispersed dry powder or particulate compositions comprising hydrocolloids, thereby avoiding the high costs of solvents and the energy associated with solvent recovery and powder production. Furthermore the method does not require emulsifying the heated carotenoid solution with an excess of an aqueous phase and an emulsifier to simultaneously form an oil-in-water emulsion. Therefore, instant disclosure gives significant cost reductions in the production and supply chain particularly for feed products.
U.S. Pat. No. 5,364,563 describes a method for preparing colloid-dispersed water-dispersible, powdered carotenoid preparations. A suspension of the carotenoid comprising 10-50% by weight of the carotenoid in high-boiling point oil is brought directly into contact with super heated steam under increased pressure and temperature and immediately cooled and emulsified in an aqueous solution of a hydrocolloid followed by spraying and drying the o/w emulsion to a powder.
U.S. Pat. No. 6,296,877, describes a method of preparing water dispersible particles or beadlets which comprises dissolving at least two hydrocolloids and a carotenoid using water miscible solvents under increased pressure and temperature. The carotenoid is immediately precipitated, in a colloidally disperse form, from the molecularly disperse solution by rapidly mixing and cooling the organic solvent solution with an aqueous solution of a swellable colloid and the resulting dispersion is freed from the solvent and the dispersing medium in a conventional manner. In common with U.S. Pat. No. 5,364,563 the method requires either solvents and/or recovery steps to obtain colloid-dispersed particulate carotenoid compositions.
U.S. Pat. No. 6,664,300 relates to a process for preparing a solution of a carotenoid in a high boiling point organic liquid to produce a carotenoid emulsion by heating a suspension of the carotenoid in a high boiling organic liquid to dissolve the carotenoid, and then immediately adding the resulting solution into an aqueous solution of an emulsifier such as a hydrocolloid, to emulsify the solution. The emulsion is spray dried to recover the colloid-dispersed carotenoid powder.
All the methods described are characterised by an essential step of emulsifying the heated carotenoid solution in excess water with a hydrocolloid and/or an emulsifier. By comparison WO03/102116 describes oil dispersible carotenoid compositions comprising lipophilic polymers/dispersants that are dissolved in oil, without applying inline and defined short heating procedures, and cooling with oil prior to preparing fish feed and other compositions.